Research On Dynamic Characteristics Of Rotor Bearing Dry Air Seal System

As high-speed turbo machinery,such as high temperature gas c ooled reactor nitrogen main fan in the actual is to develop in the direction of high performance,high parameter,the fluid flow and the rotor of fluid-solid coupling effect between the more and more significant,which affects the dynamic characteristics a nd stability of the rotor system.The development of modern equipment manufacturing technology,for the operation of the compressor unit precision demand is higher,in order to ensure the seal or device stability,reliability and durability,also must stud y the actual conditions of large s ystem.In the compressor with dry gas seal as the shaft end seal,the aerodynamic force and bearing oil film force of the impeller rotor have a great influence on the vibration of the dry gas seal system itself.Dry gas se al unit sustainable design license within the scope of the vibration,vibration is too high for a long time or surge may seal wear or damage,serious can make the dry gas seal failure,compressors will not operate properly,presses for us to solve.This paper focuses on the stability of the large s ystem of rotor,bearing and dry gas seal,which is of theoretical guiding significance for the actual use of dry gas seal.In spite of the dry gas seal dynamics has made a lot of exploration,but the application of dry gas seal under the system of nonlinear dynamic aspects of the theoretical and experimental research are very few,believe that will be doing the job after the seal dynamics research difficulty and direction.Because of dry gas seal system itself is nonlinear,sealing pressure of the Reynolds equation is nonlinear partial differential equation,the gas film force is a nonlinear transient force,the gas film vortex vibration is nonlinear vibration and sealing ring.Plus the dry gas seal system nonlinear dynamics in the study of simplified formula,selection of empirical formula is not unified,many complex dynamics theory of behavior is not strong enough to support,so that can not meet the requirements of modern unit equipment design.Based on the dynam ic system of rotor,bearing and dry gas seal system,the vibration mechanics model of the rotor-bearing-dry gas seal system and the vibration equation of the two-degree of freedom system were established.The linear Reynolds equation of the nonlinear R eynolds equation can be obtained by means of the PH linearization method.By using the variational method to divide the equation,we obtain the increment of the reaction force of the gas film under the axial perturbation,and the equation of the steady bou ndary condition is introduced.Then the analytical expressions of axial,angular stiffness and damping of the gas film are obtained.On the basis of rotor,bearing,dry gas seal system vibration model of nonlinear system by using MATLAB simulation software of Runge-Kutta to solve the double degree of freedom vibration equation,seeking stability region and optimize channel parameters,to guide the optimization design of engineering.Of spiral groove dry gas seal static ring vibration and damping were tested,choose two different groove depth of the spiral groove dry gas seal,testing the static ring,and the measured data processing and analysis,to explore different structures and different working conditions,the change rule of static ring vibration and da mping groove dry gas seal structure parameter optimization provides guidance.